The Los Angeles Times reported this week that some experts believe the problematic drywall was made using a radioactive phosphorus substance — phosphogypsum — that is banned for construction use in the U.S. but has been used by Chinese manufacturers for almost a decade.

The Los Angeles Times reported this week that some experts believe the problematic drywall was made using a radioactive phosphorus substance—phosphogypsum—that is banned for construction use in the U.S. but has been used by Chinese manufacturers for almost a decade.